BEIRUT (Reuters) - Syrian rebel group Ahrar al-Sham said on Friday that the U.S.-led coalition against Islamic State attacked a mosque near Syria's Aleppo, in a strike that a war monitor said killed dozens of people.

The Pentagon denied the accusations and, in a rare move, showed an aerial image to illustrate the mosque was intact and the building destroyed was across the street.

The Syrian Observatory for Human Rights said jets hit around a mosque in al-Jina village near Atarib in the western part of Aleppo province, a few miles (km) from Idlib province on Thursday evening.

The Observatory said the air strike had killed at least 49 people and wounded dozens, mostly civilians who were attending a religious lesson.

In Washington, Pentagon spokesman Captain Jeff Davis, said he believed dozens of al Qaeda fighters were killed in the Thursday strike by manned and unmanned U.S. aircraft on an al Qaeda meeting place in the village of al-Jina, Aleppo.

He added that the U.S. military had not yet seen any credible allegations of civilian casualties, including on social media.

Airstrikes in the area have been conducted by the United States, rather than the international coalition it leads against Islamic State, which operates further to the east. A spate of U.S. airstrikes in northwest Syria since early this year have targeted groups that have been linked to al-Qaeda.

Syrian military and Russian jets have also carried out numerous air strikes against Idlib and western parts of Aleppo province, which are held by rebels seeking to oust President Bashar al-Assad.

Ahrar al-Sham, an Islamist group that has fought alongside nationalist factions under the banner of the Free Syrian Army, has been involved in clashes this year with jihadist groups that Washington has targeted.

Ahrar al-Sham is also widely believed to be backed by Turkey and other regional states that support the rebellion against Assad. It said attacks on mosques and places of worship are considered a war crime in most legal codes.